Add support for search aliases on subgraphs (#8608)

## Summary

- add commands for setting search aliases and description when in
subgraph
- in future we can add these fields to the dialog when publishing a
subgraph
- map workflow extra metadata on save/load from from/to subgraph node to
allow access via `canvas.subgraph.extra`

## Changes

**What**: 
- new core commands for Comfy.Subgraph.SetSearchAliases &
Comfy.Subgraph.SetDescription to be called when in a subgraph context
- update Publish command to allow command metadata arg for name
- update test executeCommand to allow passing metadata arg

## Review Focus

- When saving a subgraph, the outer workflow "wrapper" is created at the
point of publishing. So unlike a normal workflow `extra` property that
is available at any point, for a subgraph this is not accessible.
To workaround this, the `extra` property that exists on the inner
subgraph node is copied to the top level on save, and restored on load
so extra properties can be set via `canvas.subgraph.extra`.
- I have kept the existing naming format matching `BlueprintDescription`
for `BlueprintSearchAliases` but i'm not sure if the description was
ever used before

## Screenshots


https://github.com/user-attachments/assets/4d4df9c1-2281-4589-aa56-ab07cdecd353

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8608-Add-support-for-search-aliases-on-subgraphs-2fd6d73d365081d083caebd6befcacdd)
by [Unito](https://www.unito.io)


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Set subgraph search aliases (comma-separated) and descriptions;
aliases enable discovery by alternative names.
  * Publish subgraphs using a provided name.
* Node definitions now support search aliases so nodes can be found by
alternate names.
  * UI strings added for entering descriptions and search aliases.

* **Tests**
* Added end-to-end and unit tests covering aliases, descriptions, search
behavior, publishing, and persistence.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

src/platform/workflow/validation/schemas/workflowSchema.ts

@@ -275,7 +275,9 @@ const zExtra = z
     frontendVersion: z.string().optional(),
     linkExtensions: z.array(zComfyLinkExtension).optional(),
     reroutes: z.array(zReroute).optional(),
-    workflowRendererVersion: zRendererType.optional()
+    workflowRendererVersion: zRendererType.optional(),
+    BlueprintDescription: z.string().optional(),
+    BlueprintSearchAliases: z.array(z.string()).optional()
   })
   .passthrough()
 
@@ -395,6 +397,10 @@ interface SubgraphDefinitionBase<
   revision: number
   name: string
   category?: string
+  /** Custom metadata for the subgraph (description, searchAliases, etc.) */
+  extra?: T extends ComfyWorkflow1BaseInput
+    ? z.input<typeof zExtra> | null
+    : z.output<typeof zExtra> | null
 
   inputNode: T extends ComfyWorkflow1BaseInput
     ? z.input<typeof zExportedSubgraphIONode>